1. Field of the Invention
The present invention relates to an apparatus for semiconductor manufacturing and more particularly, to a cleaner of a molding apparatus of semiconductor chip packages.
2. Description of the Related Arts
During a molding step, semiconductor chips mounted on and electrically connected to a lead frame or a printed circuit board are encapsulated with a molding compound, which forms a package body, for the purpose of protecting the semiconductor chips from the external environment. A conventional molding apparatus includes mold dies with cavities, each of which is in a package body shape. The semiconductor chips on the lead frame or the printed circuit board is placed in the cavities of the mold die. Then, the molding compound is injected in liquid state into the cavities and hardened.
The molding compound is mainly composed of thermosetting resin and silica particles. The mold dies are abraded by the silica particles, and the abrasion produces a gap between and in the mold dies. During the molding step, the molding compound may leak through the gap, leaving molding compound residue in and on the mold dies and thus, causing troubles in the next molding. Accordingly, the molding step is accompanied by a cleaning step for removing the molding compound residues from the mold die.
With reference to FIGS. 1a and 1b, which illustrate a conventional cleaner for a molding apparatus, a conventional cleaning step is explained.
Referring to FIGS. 1a and 1b, a molding apparatus 200 includes a cleaner 230 placed next to a molding die set 210. The molding die set 210 consists of an upper molding die 211 with cavities and a lower molding die 212. The cleaner 230 includes a cleaning head 231, and a motor 243 that provides vibration motion to the cleaning head 231. The motor 243 is connected to the cleaning head 231 by a concentric shaft 245. The cleaning head 231 includes a brush 234 for separating the resin residues from the molding die set 210, and a vacuum hole 241 for sucking the resin residues. The vacuum hole 241 is connected to a vacuum hose 259 and further to an external vacuum suction means (not shown).
After unloading the semiconductor packages from the molding die 210 by separating the upper molding die 211 and the lower molding die 212 from each other, the cleaning head 231 advances to between the upper molding die 211 and the lower molding die 212. Then, the brush 234 vibrates and separates the resin residues from the molding die 210. The separated resin residues are removed through the vacuum hole 241. This cleaning step is carried out after each molding step.
After a number of molding and cleaning steps, a step for coating a parting compound is carried out. The parting compound serves to easily remove the semiconductor packages from the molding dies. In the parting compound-coating step, the molding apparatus executes at least one molding step using an epoxy molding compound having a large quantity of the parting compound, in order to coat the parting compound on the surface of the molding dies.
The above-described molding step has several problems. The parting compound-coating step is carried out by stopping the normal operation of the molding apparatus, and the molding compound having the parting compound is supplied into the molding apparatus manually by an operator. Therefore, the production rate of the semiconductor packages is limited.
An aspect of the present invention provides an apparatus for cleaning a mold die set. The apparatus includes a pair of brushes, a pair of vacuum holes, and multiple nozzles. One of the brushes is positioned to scrub a first surface of the mold die set, and the other of the brushes is positioned to scrub a second surface of the mold die set to separate a residue from the first and second surfaces of the mold die set. The brushes vibrate to perform the scrubbing. The vacuum holes receives the separated residue from the first and second surfaces of the mold die set, and through the nozzles, a parting compound is provided to coat the parting compound on the first and second surfaces of the mold die set. The parting compound is provided by spraying from the nozzles. The apparatus further includes multiple air holes through which air is blown to the first and second surfaces of the mold die set.
Another aspect of the present invention provides an apparatus for semiconductor manufacturing. The apparatus includes a mold die set having a first surface and a second surface and a mold die set cleaner that can remove a residue from the first and second surfaces of the mold die set and coat a parting compound on the first and second surfaces. The mold die set cleaner includes: a brush that scrubs the first surface of the mold die set to separate the residue from the first surface; a vacuum hole that receives the separated residue from the first surface of the mold die set; and nozzles through which a parting compound is provided to coat the parting compound on the first surface of the mold die set. The mold die set cleaner further includes air holes through which air is blown to the first and second surfaces of the mold die set. The mold die set cleaner also further includes: a second brush that scrubs the second surface of the mold die set to separate the residue from the second surface of the mold die set; other nozzles through which the parting compound is provided to coat the parting compound on the second surface of the mold die set; and a second vacuum hole that receives the separated residue from the second surfaces of the mold die set.